Vehicle head restraints extend above a seatback of a vehicle seat. Known head restraints are typically adjustable in a vertical direction. Some known head restraints are also adjustable in a longitudinal direction, i.e., in the direction of travel for the vehicle. Of these known head restraints that are longitudinally adjustable, some include a rack and pinion arrangement. One such longitudinally adjustable head restraint includes a pinion that is rotated by an operator turning a knob. Another known longitudinally adjustable head restraint includes a pinion that is moveable after depressing a laterally disposed actuator member. Many known longitudinally adjustable head restraints tend to include a complicated or cumbersome locking mechanism.